Juan Carlos Munoz / Gomantong caves with ladder for collecting Swiftlet nests, River Sungai Kinabatangan, Sabah, Borneo, Malaysia 2007

Suzi Eszterhas / Glossy swiftlets (Collocalia esculenta) in cave, Sabah, Malaysia

Suzi Eszterhas / Glossy swiftlets (Collocalia esculenta) in cave, Sabah, Malaysia

Duncan Murrell / Palawan swiftlets (Aerodramus palawanensis) returning to the subterranean river cave, Puerto Princesa Subterranean River National Park UNESCO World Heritage Site, Palawan, the Philippines. Endemic to...

Emanuele Biggi / Remains of a dead swiftlet on cave floor, Borneo, Sarawak, Malaysia.

Emanuele Biggi / Dead swiftlet being eaten by darkling beetles and cockroaches. Deer cave, Gunung Mulu National Park, Borneo, Sarawak, Malaysia

Emanuele Biggi / Mossy-nest swiftlet (Aerodramus salangana natunae) chicks at nest, Deer Cave, Gunung Mulu National Park, Borneo, Sarawak, Malaysia.

Ingo Arndt / Christmas Island Glossy Swiftlets (Collocalia linchii natalis) breeding colony in cave, Christmas Island, Indian Ocean, Australian Territory, endemic

Ingo Arndt / Christmas Island Glossy Swiftlets (Collocalia esculenta natalis) breeding colony in cave, Christmas Island, Indian Ocean, Australian Territory. (These birds are endemic to Christmas Island)

Ingo Arndt / Christmas Island Glossy Swiftlets (Collocalia esculenta natalis) breeding colony in cave, with pile of excrement in foreground. Christmas Island, Indian Ocean, Australian Territory. (These birds are e...

Christophe Courteau / Cockroaches (Periplaneta americana) feeding on a dead chick of Black-nest swiftlet (Aerodramus maximus) which fell from its nest in Gomantong Cave. Sabah State. Borneo. Malaysia.

Nick Garbutt / Edible nests of Black-nest swiflet (Aerodramus maximus / Collocalia maxima) and White edible-nest swiftlet (Aerodramus fuciphagus / Collocalia fuciphaga). Nests collected from Gomantong Caves, Sabah,...

David Tipling / Edible-nest Swiftlet (Aerodramus fuciphagus) nests on sale in medicine shop for making birds nest soup, Singapore.

David Tipling / Blue-faced Honeyeater (Entomyzon cyanotis) captive from New Guinea and Australia.

David Tipling / Glossy Swiftlet (Collocalia esculenta) nesting inside house, Cebu, Philippines.

David Tipling / Edible Nest Swiflet (Aerodramus fuciphagus) nests on sale in medicine shop in Singapore for making birds nest soup, Singapore, August 2011

David Tipling / Edible Nest Swiflet (Aerodramus fuciphagus) nests on sale in medicine shop in Singapore for making birds nest soup, Singapore, August 2011

Juergen Freund / Bird hotel for Edible nest swiftlets (Aerodramus fuciphagus) to harvest birds nests for bird nest soup. Kumai port, Central Kalimantan, Indonesian Borneo

Juergen Freund / Bird hotel for Edible nest swiftlets (Aerodramus fuciphagus) to harvest birds nests for bird nest soup. Kumai port, Central Kalimantan, Indonesian Borneo

Konrad Wothe / Edible-nest swiflet (Aerodramus fuciphagus inexpectata) on nest, Challis Ek Caves, North Andaman, Andaman Islands, India

Juergen Freund / Ring of Swiftlet (Aerodramus sp) nests on roof of cave. Raja Ampat, West Papua, Indonesia, February 2010.

Juergen Freund / Swiftlet (Aerodramus sp) on nest attched to inside of cave. Raja Ampat, West Papua, Indonesia, February.

Juergen Freund / Swiftlet (Aerodramus sp) nest with two eggs, attached to wall inside a cave, Raja Ampat, West Papua, Indonesia, February.

Chien Lee / Mossy-nest Swiftlet (Aerodramus salangana) chicks, less than two weeks old, in nest made on a stalagtite within a limestone cave, Bau, Malaysia

Ingo Arndt / Cave Swiftlet (Collocalia linchi) breeding colony in cave, Christmas Island, Indian Ocean, Territory of Australia

Ingo Arndt / Cave Swiftlet (Collocalia linchi) breeding colony in cave, Christmas Island, Indian Ocean, Territory of Australia

David Tipling / Glossy swiftlets (Collocalia esculenta) inside dwelling near nest, Cebu, Philippines

David Tipling / Glossy swiftlet (Collocalia esculenta) nesting inside dwelling, Cebu, Philippines

Juan Carlos Munoz / Inside the Gomantong caves with ladder for collecting Swiftlet nests, River Sungai Kinabatangan, Sabah, Borneo, Malaysia 2007

Juan Carlos Munoz / Inside the Gomantong caves with ladder for collecting Swiftlet nests, River Sungai Kinabatangan, Sabah, Borneo, Malaysia 2007

Konrad Wothe / Edible-nest Swiftlet (Aerodramus fuciphagus) on nest, North Andaman Islands, India

Konrad Wothe / Edible-nest Swiftlet (Aerodramus fuciphagus) on nest, North Andaman Islands, India

Konrad Wothe / Edible-nest Swiftlet (Aerodramus fuciphagus) nest with eggs, North Andaman Islands, India

Konrad Wothe / Edible-nest Swiftlet (Aerodramus fuciphagus) nest with eggs, North Andaman Islands, India

Konrad Wothe / Edible-nest Swiftlet (Aerodramus fuciphagus) nest with eggs, North Andaman Islands, India

Phil Chapman / Black nest swiftlet chicks in nest {Aerodramus maximus} in Gua Nasib Bagus cave, part of Gunung Mulu NP, Sarawak, Borneo

Phil Chapman / Mossy nest swiftlet eggs in nest in cave {Aerodramus salangana} Sarawak, Indonesia

Phil Chapman / Black nest swiftlet chick and eggs in nest. Sarawak, Borneo, Nasig Bagus caves, Mulu

Phil Chapman / Black nest swiftlet chicks in nest in cave. Sarawak, Borneo {Aerodramus maximus}

Juergen Freund / Gomantong caves - collecting site for Cave swiftlet nests, Sabah, Borneo, Malaysia.

Julian Hume / Illustration of Mauritian birds. Mauritius pink pigeon (Nesoenas mayeri) (centre left); Mauritius fody (Foudia rubra) (centre right); Mauritius olive white-eye (Zosterops chloronothos) feeding on the...

Phil Chapman / Cave racer snake {Elaphe taeniura} predating Swiftlet, Mulu caves, Sarawak, Borneo, Malaysia

Roland Seitre / Grey-rumped swiftlet (Aerodramus francicus) in flight, Ebony forest Charmarel, Mauritius.